Materials with high magnetostriction

The magnetostrictive properties of cubic Laves phases such as TbFe 2 , Terfenol D and SmFe 2 are summarised. It is shown that SmFe 2 can be an interesting candidate as a high magnetostrictive material even in the as cast "dirty" state. Fe-X alloys based on Fe-Ga but also Fe-Al are presented as materials with a medium magnetostriction, however with the big advantage of a magnetically soft material. Generally all nonmagnetic substutional elements which cause an increase of the interatomic distance in the Fe-lattice (such as Ga, Al, Si) cause an increase of the magnetostriction too. In Ni-Ga a reduction of the magnetostriction was found. Another interesting material with high magnetostriction is CoFe 2 O 4 which is cheap, easy to produce and an oxidic material. Here magnetostriction values up to 400 ppm can be achieved by hydrostatic compaction followed by a field annealing.